1. Field of the Invention
This invention relates to a device for dissipating heat generated from an electronic device, and more particularly to a heat dissipation device, which is provided with a plurality of ribbed fin plates, thereby increasing the heat dissipating effect thereof.
2. Description of the Related Art
Nowadays, because electronic devices are getting more and more compact, heat quantity generated per unit volume of the devices is on the rise. As a result, there is a need to promote the heat dissipating ability of the electronic device. Referring to FIG. 1, a conventional heat dissipation device 2 is shown to include a thermally conductive horizontal base plate 20 and a plurality of parallel vertical heat-dissipating fin plates 21 that extend integrally and upwardly from the base plate 21 and that have flat side surfaces. The base plate 20 abuts against and is in thermal communication with a heat-generating horizontal plate 1 of an electronic device. Each adjacent pair of the fin plates 21 defines a channel 22 therebetween, through which cool air is forced to flow. As such, during heat conduction in the fin plates 21, heat is concentrated in lower portions thereof, thereby decreasing the heat dissipating effect of top portions of the fin plates 21. Furthermore, when the cool air flows through the channels 22, the thickness of the temperature boundary layer of the air increases from the upstream ends of the channels 22 to the downstream ends of the channels 22, thereby decreasing the heat dissipating effect of the portions of the fin plates 21, which define the downstream portions of the channels 22. Referring to FIG. 2, another conventional heat dissipation 3 is shown to also include a base plate 30 and a plurality of heat-dissipating fin posts 31, which define a grid-shaped channel unit 32 that permits flow of air therethrough. Although heat can be transferred through the posts 31 from lower ends to upper ends, it is difficult to discharge air from the channel unit 32. Because the air cannot carry heat effectively from the base plate 30, the heat dissipating effect is relatively poor.
An object of this invention is to provide a heat dissipation device with a plurality of ribbed and elongated fin plates, each of which permits heat transfer therein from one end to another end and from one side to another side and which can guide the flow of cool air, thereby increasing the heat dissipating effect.
According to this invention, a heat dissipation device includes a thermally conductive base plate and a plurality of thermally conductive fin plates that are in thermal communication with the base plate. Each adjacent pair of the fin plates defines a channel therebetween, through which cool air is forced to flow. Each of the fin plates has a proximate side that is proximate to the base plate, a distal side that is opposite to the base plate, and a plurality of integral ribs that extend from the proximate side to the distal side, thereby permitting heat transfer from the proximate side to the distal side along the ribs. Because each of the ribs enables formation of a small turbulent flow of the cool air, a temperature boundary layer of the air is broken in each of the channels, thereby permitting heat transfer from upstream ends of the channels to downstream ends of the channels. In addition, because the sizes of the ribs are relatively small with respect to the widths of the channels, the cool air can flow smoothly through the channels.